Low voltage heating means



Sept. 18, 1956 J. LYON LOW VOLTAGE HEATING MEANS Filed Jan. 6, 1953 jameslsfgzNToR Mg/14% ATTORNEY United States Patent O 2,763,766 LQ P AGE swims Juri s .Lr niSan D go, Qant- Application Ianuaryfi, 1953, SerialNo. 329,763 91- 21 This invention relates .to a new and novel low voltage heating meansawhich is suitable for use on assembly lines and repair shops and it consists in the constructions,

sa s ab ish s herein described and consistency and temperature, which is likewise true of the oven and other attachments which may be employed.

More specifically, it is an object of the invention to provide a compact unit for housing a transformer, heat control, exhaust fan, control switch and a lead in for connection to a suitable source of current, the transformer having respective terminals disposed adjacent an opening in the housing, whereby various instrumentalities may be interchangeably connected to the terminals of the transformer.

It is a still further and important object of the invention to provide a pot or the like which is temperature controlled, especially suitable for melting solder to a proper consistency and maintaining the solder at a proper temperature so pig-tails or like connectors may be bonded to terminals of electrical devices or to component parts of electronic assemblies by placing the connector and terminal in physical contact and dipping both into the molten solder.

Additional objects, advantages and features of invention will be apparent from the following description, considered in conjunction with the accompanying drawing, wherein,

Figure 1 is a perspective view of the unit.

Figure 2 is a top plan view of the unit partly in section.

Figure 3 is a perspective view of a solder melting pot.

Figure 4 is a perspective view of an oven which may be employed with the unit.

Figure 5 is a perspective view of a further form of heating unit, and

Figure 6 is a diagrammatic view of the electrical circuit of the unit.

Attention is invited to Figures 1 and 2 of the drawing wherein there is shown a housing unit 10 consisting of a bottom wall 11, respective side walls 12, front wall 13, rear wall 14 and a top wall 15, the walls being secured together in any approved manner to provide a sturdy construction.

The front wall 13 is formed with an opening 16 and the rear wall 14 is formed with an opening 17, as best seen in Figure 2.

A 200 watt transformer 18 is suitably secured within the housing 10, having a current conducting line 19 secured to one side of the transformer. The line 19 is electrically connected to a line 20 of a conductor 21, the latter having a connector plug 22 which may be plugged into any conventional 110 volt circuit. A current conducting line 23 from the transformer is connected to one side of a rheostat 24, the opposite side of the rheostat being in electrical circuit w'th a line 25 of the conductor 21. The rheostat controls the current passingthrough the transformer 18.

7 Current conducting element 26 and 27 are in electrical connection with the transformer 18 and as shown in Figure 1 are suitably secured to the inside of the front wall 13 of the housing and are so positioned as to be exposed in advance of the opening 16. The lower ends of the current conducting elements are formed with threaded extensions for mounting of suitable receptacles or the like, as will now be described, attention first being invited to Figure 3 of the drawing. In this figure, "a miniature solder pot 28 is Welded to a strip of resistance metal 29, the ends projecting beyond respective sides thereof and upon the underside of said ends, a bracket arm 30 is spot welded, these arms being spaced apart to align withthe current conducting elements 26 and 2 7. In order tosecure the arms 30 to the current conducting elements, a right angularly disposed ear 31 is formed theredn having an aperture for registry with athre aded stud 32 theassemblage being completed by means of nuts 32'. The arms 30 are preferably iron strips, plated to resist corrosion and to increase conductivity.

In Figure 4 a miniature oven 33 is shown, the back 34, sides 35 and top 35' being formed of resistance metal, divided so as to provide an electrical circuit between brackets 37 and 38', while the front 36 is asbestos lined. The brackets 37 and 37 corresponding to the arms 30 are apertured to receive fastening means for securing the oven upon the current conducting elements 26 and 27.

In Figure 5, a further form of the heating device is shown, particularly useful for immersion in liquids, for rapid heating thereof or for maintaining the liquid at a desired temperature. The immersion heater indicated at 38 comprises a pair of parallel legs 39, the lower ends of which are bent at right angles thereto and have welded thereon a strip of resistance metal 40. The upper ends of the legs 39 are slightly ofiset from the vertical as indicated at 41 enabling proper mounting of the heater to the conductors 26 and 27 and present the strip 40 in spaced relation to the wall 13 of the unit so that it may be readily immersed in a liquid filled receptacle. The legs 39 are preferably constructed from iron strips which are plated to resist corrosion and are also provided with a number of vertically spaced apertures 39 for adjustably securing the legs to the current conducting elements 26 and 27.

A switch 42 is employed for controlling the flow of current to the fan from a suitable source of electrical current. The switch 42 has a line 45 connected to line 25 of the conductor 21 and a line 46 is connected to one terminal of the motor of the fan 43; the other terminal of the motor of the fan having a line 47 which is in circuit with the line 2% of the conductor 21. The light 44 is electrically connected to line 20 of the cable 21 and to line 23 of the rheostat, and while the light 44 is not essential to the operation of the heater, it serves as a signal means to indicate that the heater is connected. The fan 43 may likewise be eliminated where desired without eifecting the operation of the heater, though in certain situations it is desirable to have a means for withdrawing annoying fumes and gases, by creating a circulation of air through the openings 16 and 17.

With the heating unit installed in a volt circuit, the solder pot or other heating device will in the matter of a few seconds be brought to a desired temperature by adjusting the rheostat and will be maintained at such temperature, so that, in the case of the solder pot, the solder is directly heated and will be of the proper consistency, in order that electrical connections such as pigtails may be readily tinned by a mere dipping operation.

In actual practice it has been found that a neater and more permanent connection can be obtained as compared to the present practice and also preheating of the pigtail or other connector is eliminated.

'It should be noted that in all cases, the heating device per se is heated by passage of high amperage, low voltage current, thus eliminating the conventional heating coils or other elements, as now employed in soldering pots and irons, and therefore makes for greater efliciency, since there is an ideal and direct transfer of heat to the heating attachments. It will also be noted that in the present heating attachments, the need for electrical and thermal insulation is avoided.

Many uses have been found for the device, among which are the melting of metals other than solder; vaporizing chemicals, conditioning plastics, and heating liquids, while the oven has been found useful in certain laboratory work.

While preferred forms of the device has been shown and described, this is by way of illustration only, and I consider as my own, all such modifications in construction as fairly fall within the scope of the appended claim.

I claim:

A heater unit comprising a housing having an opening in one end thereof, an electrical circuit including a transformer of high amperage and low voltage current within References Cited in the file of this patent UNITED STATES PATENTS 475,189 Burton et al May 17, 1892 494,585 Mitchell Apr. 4, 1893 1,370,631 Clark Mar. 8, 1921 1,684,942 Carleton Sept. 18, 1928 1,738,908 Kuhn et al. Dec. 10, 1929 1,816,711 Berresford July 28, 1931 1,949,450 Brown Mar. 6, 1934 2,070,491 Park Feb. 9, 1937 2,182,383 Lang et al. Dec. 5, 1939 OTHER REFERENCES Strong et al.: Procedures in Experimental Physics, Prentice-Hall, Inc., 1946; p. 176. 

